This overview is a sample of the type of information available to you at Griffin Hospital's Community Health Resource Center. It is not intended to replace your physician's instructions in the management of your health problems, but to better inform you about a particular illness and alert you to the availability of other materials. If you have a question about any piece of information presented in theses fact sheets, please call your physician, or stop by the Community Health Resource Center at your convenience.

MRI

MAGNETIC RESONANCE IMAGING

Magnetic Resonance Imaging (MRI) is a test that gives a sharp and detailed picture of soft tissue in the body. Because the MRI can take pictures through bone, it is used when additional information is needed that is not able to be obtained from other common tests, such as an x-ray or computed tomography (CT) scan. The MRI can assist a doctor in making or confirming a diagnosis, or provide more specific information about a known problem.

The MRI test is not invasive and is not painful. Sometimes the doctor requests that a dye be used and this is injected into your vein before the test. The MRI is usually done at a hospital or testing center.

WHO NEEDS AN MRI?

An MRI is used by physicians to help diagnose many conditions. It is most often used for people with suspected soft tissue problems in the brain or spinal cord, low back problems, or injuries which involve tendons and ligaments. It may also be used to obtain an image of other organs and parts of the body. Because the MRI is a very advanced type of test, it is also costly and is not be used routinely. Many problems are more accurately diagnosed by x-ray or CT scans. In addition, the accuracy level of the MRI may not be as high as that of other tests. The results of an MRI must be analyzed by a doctor who can determine the significance of the results as they relate to the individual. The MRI should not be used as a substitute for a thorough medical examination or other tests.

WHAT DO I DO BEFORE THE TEST?

In order to take the pictures, a very strong magnetic field is created. You will need to remove any metal objects from your body or on any of your clothing before the test. This includes jewelry, hair pins, watches, dentures, and even cards in your wallet with magnetic strips. If you have a pacemaker, metal joint, or any other medical device that has been implanted in your body, let your doctor know. You will need to lie still for up to 30 minutes while the pictures are being taken so you may want to avoid drinking coffee or tea just before the test.

HOW DOES IT WORK?

The MRI is a large metal machine shaped like a tunnel. For the test, you will lie on a narrow, padded surface that will be slid inside the machine. The cylinder is narrow but there are fans inside to circulate air and mirrors to allow you to see the room and the person who is operating the equipment. There is an intercom through which you and the operator can talk. During the test, you will hear metallic thumping sounds. This is normal but bothers some people. Some scanners have earphones so you can listen to music or relaxation tapes. The operator can also see you through a camera while you are in the scanner and will talk with you to give you instructions while the pictures are being taken. The pictures are taken from all different angles without you moving at all.

The test usually takes less than 30 minutes, during which you will be asked to lie still so the pictures will be clear. The results of the MRI are then sent to your doctor who will review them with you.

WHAT ARE THE RISKS?

If you have a tendency to feel claustrophobic (highly anxious when confined in a small space), discuss this ahead of time with your doctor. The test operator can demonstrate to you how quickly you can be removed from the scanner. Sometimes a friend or relative can sit in the room with you. You can also try to do relaxation and breathing exercises or ask your doctor to give you a light sedative before the test.

There are no known health risks for this test, although the test is not generally done in women who are pregnant. The only danger of the test is from injury caused by the strong magnetic field, which can send metal objects flying through the air. The test can also interfere with equipment such as pacemakers and internally implanted devices, so it is important to let your doctor know so they can prepare in advance for this.

Please note that this information is intended to give you a general overview of the topic. It is not intended to replace advice or instruction of a health professional. We recommend that you consult your physician, nurse, or qualified health professional regarding the information in this publication. © 1994 Planetree, Inc. Reproduction of this material in any form is limited to license agreement.

Planetree Health Fact Sheets are developed by Planetree, Inc., a non-profit consumer health organization, founded in 1978. The Planetree Alliance includes hospitals and libraries which, among many other patient-centered concepts, promote the importance of access to health information for patients, families, and community. For more information regarding affiliation with the international Planetree Alliance, call (203) 732-1365 or visit Planetree, Inc. at www.planetree.org.